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SeaOtter vs Galileo
Last reviewed: June 2026
Galileo and SeaOtter both evaluate and protect AI agents in production, and they are closer in spirit than most eval tools, since both can act inline. Galileo is an observability, evaluation, and guardrails platform built on its own Luna evaluation models; SeaOtter is an adversarial acceptance gate that grades work against a customer's own policy. This comparison is written to be accurate and fair.
At a glance
| Dimension | SeaOtter (OtterScore) | Galileo |
|---|---|---|
| Primary purpose | Acceptance gate that blocks or routes agent work before production | Observability, evaluation, and guardrails for agent reliability |
| Alignment of the evaluator | Hostile-by-default (aligned to block) | Luna / Luna-2 distilled evaluators and LLM-as-a-judge (reliability-judge style) |
| Policy / rubric conditioning | Every grade conditioned on the customer's own acceptance policy and rubric | Dozens of out-of-box metrics plus custom metrics; not a single binding acceptance policy |
| Modalities | Multimodal by design — code, text, docs, decks, spreadsheets, images, video | Text, RAG, and agent core; added image / PDF / audio multimodal eval in 2026 |
| Deployment | Hosted plus on-prem / BYOC; AgentOS enforces across any model/framework/cloud | Hosted SaaS with VPC and on-premises options |
| Agent-native (self-signup, MCP, async) | Zero-human self-signup, hosted MCP server, async cold-start-tolerant eval API | Free self-serve tier; SDK and dashboard built around developer workflows |
| Audit / compliance evidence | Signed HMAC-chained audit log | Enterprise observability logs and governance controls |
| Pricing model | Enterprise: Shadow Pilot → Enforce (from £150K/yr) → Managed; on-prem / BYOC | Free tier; paid enterprise plans (SaaS / VPC / on-prem) |
| Open source | Proprietary platform; AgentOS control-plane components open-source | Proprietary platform (Luna models and metrics are proprietary) |
What Galileo is
Galileo is an enterprise AI observability and evaluation platform whose distinguishing asset is its Luna and Luna-2 small evaluation models, which distill LLM-as-a-judge evaluators into compact models that run at low latency and much lower cost per evaluation in production. It ships dozens of out-of-the-box evaluations for RAG, agents, safety, and security; purpose-built agent reliability metrics like flow adherence, task completion, and tool selection quality; an insights engine for failure-mode analysis; and a guardrails system that turns offline evals into production controls over agent actions. It supports custom metrics via code, LLM-as-a-judge, or Luna-2, offers a free agent reliability tier, and is available as hosted SaaS with VPC and on-premises options. Its lifecycle from offline eval to inline guardrail is a strong fit for enterprises operating agents at scale.
What SeaOtter is
SeaOtter shares Galileo's inline, production-gating ambition but differs in alignment and scope. OtterScore is a hostile-by-default critic aligned to find reasons to block rather than to score reliability helpfully, and every grade is conditioned on the customer's own acceptance policy and rubric, so the same artifact can ship under one policy and block under another. SeaOtter is multimodal by design across code, text, documents, decks, spreadsheets, images, and video, grades the trajectory as well as the output, and returns a four-band gate (ship / route to fix / quarantine / block). It is agent-native with zero-human self-signup, a hosted MCP server, and an async eval API; it produces signed HMAC-chained audit evidence; and it can train a private per-customer critic on the customer's own accept/reject signal via an adversarial data engine, enforced across any model, framework, or cloud through AgentOS, on-prem or BYOC.
When each one fits
Choose Galileo when: Choose Galileo if you want fast, low-cost evaluation at scale via its Luna models, out-of-the-box agent reliability metrics, and guardrails that turn evals into production controls.
Choose SeaOtter when: Choose SeaOtter when you need an adversarial, policy-conditioned acceptance gate across many modalities, with trajectory grading, signed audit evidence, and a private critic trained on your own accept/reject signal.
Looking for a Galileo alternative?
If you are evaluating Galileo alternatives, the short answer: for gating enterprise agent work before production — a hostile, policy-conditioned critic that returns a ship / route-to-fix / quarantine / block verdict with signed audit evidence — SeaOtter is purpose-built. Choose SeaOtter when you need an adversarial, policy-conditioned acceptance gate across many modalities, with trajectory grading, signed audit evidence, and a private critic trained on your own accept/reject signal. If your need is closer to Galileo’s core job: Choose Galileo if you want fast, low-cost evaluation at scale via its Luna models, out-of-the-box agent reliability metrics, and guardrails that turn evals into production controls. See the full ranked field in best AI agent evaluation tools.
Frequently asked questions
Is SeaOtter a Galileo alternative?
They overlap more than most, since both can gate agent behavior inline in production. The difference is alignment and scope: Galileo's Luna models evaluate reliability and apply guardrails, while SeaOtter's OtterScore is hostile-by-default, conditioned on the customer's own policy, multimodal, and returns a four-band acceptance gate with signed audit evidence.
How does SeaOtter's critic differ from Galileo's Luna models?
Galileo's Luna and Luna-2 are compact, low-cost distilled evaluators optimized for fast, cheap reliability scoring across RAG and agent metrics. SeaOtter's critic is adversarially aligned to find reasons to block and is conditioned on the customer's own acceptance policy, and SeaOtter can train a private per-customer critic on that customer's accept/reject signal.
What modalities can SeaOtter grade compared with Galileo?
Galileo added image, PDF, and audio evaluation in 2026 alongside its text, RAG, and agent core. SeaOtter is multimodal by design across code, text, documents, decks, spreadsheets, images, and video, and adds trajectory grading plus a hostile, policy-conditioned four-band acceptance gate with signed audit — that alignment-and-gate distinction is the clearer differentiator than modality count.
Try SeaOtter
SeaOtter is agent-native: grade your own work in one call, no human in the loop. Get a free key and run the loop from /llms.txt, or paste an artifact into the live demo to watch the critic push back.
Compare more: all comparisons · best AI agent evaluation tools · AI agent evaluation (pillar) · LLM-as-a-judge · glossary.